This invention relates to a new method and apparatus for detecting lameness in animals and promoting animal well-being. The preferred embodiment of this invention is for detecting lameness in four legged animals, such as but not limited to horses, dairy cows, non-dairy cows, pigs, and sheep.
Dairy production is an important industry in the U.S. and a major branch of agriculture in many countries around the world. Cow lameness caused by hoof and leg ailments is a costly problem for the dairy farmer. Lameness necessitates medical treatment, reduces milk production, results in decreased body condition, impairs reproduction performance, and adversely impacts the social status of animals. Economically, lameness is reported to be the third most costly problem for dairy herds following mastitis and sub-fertility. The average cost of lameness is reported to be 412 dollars per incident and the annual incidence rate in the U.S. is fifteen percent. Thus, the annual economic losses due to lameness is over 570 million dollars for the over nine million U.S. cows. These losses significantly impair dairy farms and harm the entire bovine industry.
In addition to the economic impact, lameness is also recognized as an important animal welfare issue. The 1993-94 Annual Report of the Animal Welfare Foundation of the British Veterinary Association states that xe2x80x9c. . . if it were possible to substantially reduce the incidence of lameness, this single initiative, more than any other would benefit more animals than any other (initiative) . . . .xe2x80x9d Thus, researchers have focused on developing a means of detecting hoof and leg ailments at their early onset.
Lameness in dairy herds has been reported to be a critical economic factor and a vital animal-welfare issue for the dairy industry around the world. Various lameness evaluation schemes that assess the severity of the ailment, using non-clinical personal, have been suggested. These schemes are based on visual observations of individual cattle. In one scheme, lameness scoring is based on the shape of the cow""s back both as the animal stands and as the animal walks. However, although this scheme lends itself to field use, its results are highly subjective and are non-quantitative in nature.
There are reports of management programs to control lameness and studies of the housing factors that influence the locomotion of dairy cows. Some of the etiological factors contributing to lameness are nutrition, bacterial and fungal infections, bacterial endotoxin, environmental conditions, housing, flooring, feeding management, and cow behaviors. The fact that many different factors lead to lameness makes it almost impossible to eliminate hoof and leg ailments and imposes difficulties for diagnostic procedures. Early detection of hoof and leg ailments is not a yet reality and most farmers record an incidence of lameness only at the stage when the cow is crippled. Thus, there is a need in the art for a method and an apparatus able to provide early detection of hoof and leg problems, which will enable prompt veterinarian medical intervention to reduce economic losses, lessen the pain that the animal endures, and expedite the animal""s recovery process. Furthermore, an early detection system will facilitate scientific testing of management programs designed to reduce the rate of incidence of lameness in dairy herds and will promote animal well-being.
A research effort that analyzes the gait of horses and detects lame limbs is reported in Schamhardt, H. C. and Merkens, H. W., xe2x80x9cObjective determination of ground contact of equine limbs at the walk and trot: comparison between ground reaction forces, accelerometer data and kinematics,xe2x80x9d Equine Vet. J Suppl. No. 17, pp. 75-79, 1994. In this study, the animal is led over a single force plate and a Horse (xe2x80x9cHxe2x80x9d) index is calculated. However, this method and apparatus only detected the force of one of the animal""s limbs. To obtain forces from each of the animal""s limbs, four separate tests would have to be performed. Therefore, even though a set of forces could be obtained for each limb, such data was merely a compilation of four or more separate tests wherein the speed of the animal, as well as other variables, varied in each run. To detect lameness, the H value is compared with a previously calculated sound horse model. This type of system and index are not available for detecting lameness in dairy cows and they are not as sensitive and versatile as the system described herein. In particular, the H index relies on leading a horse multiple times across a measuring device under the assumption that the speed of the horse remains constant during all measurements.
This invention relates to a method and apparatus for detecting lameness in animals and for promoting animal well-being, wherein one or more force places are configured to detect forces generated by an animal and these forces are utilized to determine the soundness of an animal.
Additional advantages and other features of the present invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the invention. The advantages of the invention may be realized and obtained as particularly pointed out in the appended claims.
In one aspect, the invention comprises a computer-based diagnostic system to detect and analyze ground reaction forces produced by an animal passing through the diagnostic system, comprising a first plate and a second plate disposed adjacent the first plate. A first plurality of load cells is also provided, wherein each of the first plurality of load cells is configured to detect a force applied to the first plate along at least one axis and output at least one signal representative of the detected force. Similarly, a second plurality of load cells is provided, wherein each of the second plurality of load cells is configured to detect a force applied to the second plate along at least one axis and output at least one signal representative of the detected force. A processor adapted to execute at least one force analysis instruction set is provided to, in combination with the force analysis instruction set, receive signals output from the first and second plurality of load cells and calculate a magnitude and location of a force applied to each of the first plate and the second plate. In another aspect of this diagnostic system, a length each of the first plate and the second plate is selected to be greater than a distance traversed by the animal at a standard walking gait of the animal so that each limb of the animal contacts a respective one of the first plate and second plate at least once. In other words, this aspect of the invention permits all measurements to be made during a single pass of the animal through the system thereby ensuring that all measurements are made at a single transversal speed. Other aspects of the invention include incorporation of speed sensors to obtain the average or instantaneous speed(s) of an animal through the system.
In another preferred aspect, the invention comprises a computer-based method for detecting and analyzing ground reaction forces produced by an animal, comprising the steps of guiding an animal to move across an instrumented force-sensing floor comprising a left floor plate, a right floor plate, a plurality of left floor plate load cells configured to measure a force applied to the left floor plate and output a force proportioned signal, and a plurality of right floor plate load cells configured to measure a force applied to the right floor plate and output a force proportioned signal; constraining at least one of the animal""s lateral body movement and leg movement so that the animal""s left limbs contact the left floor plate and the animal""s right limbs contact the right floor plate; calculating forces applied to the left floor plate and to the right floor plate by summing the signals output by the left floor plate load cells and right floor plate load cells, respectively; and comparing the calculated forces to a range of forces indicative of at least one of a sound animal condition, an indeterminate animal condition, or a lame animal condition.
Still another aspect of the invention includes a computer-readable medium bearing instructions enabling a computer having at least one processor to detect and analyze ground reaction forces produced by an animal to determine a physical condition of the animal, the instructions, when executed by a computer, causing the computer to carry out the steps of calculating ground reaction forces produced by the animal by summing the force proportioned signals output by load cells separately measuring loads of each of a left floor plate and a right floor plate and comparing the calculated forces to a range of forces indicative of at least one of a sound animal condition, an indeterminate animal condition, or a lame animal condition.